Shaft control means



June 14, 1960 w. R. JUDD 2,940,564

SHAFT CONTROL MEANS Filed Oct. 24, 1957 I j g f Billll nited States Patent SHAFT CONTROL MEANS Winston R. Judd, Pittsfield, Mass, assignor to General Electric Company, a corporation of New York Filed Oct. 24, 1957, Ser. No. 692,154 4 Claims. (Cl. 192-8) This invention relates to means for controlling the rotation of a shaft, and more in particular to means whereby a shaft may be manually rotated from a control means but will not respond to torque generated remotely from the control means, the control means thereby serving to lock the shaft and prevent injury to personnel operating the control. While the inventionis specifically disclosed in the following paragraphs as relating to a control for manually operated induction voltage regulators, it is not intended that the invention be limited to this application.

One form of induction voltage regulator is comprised essentially of a rotor and stator having windings, the windings being adapted to be connected to an electrical circuit :whereby the voltage of the circuit will be determined by the angular position of the rotor. When current flows through the windings of the regulator, motor torque is generated in the rotor, and thus in order to maintain the position of the rotor and thereby maintain the voltage of the electric circuit, it is necessary to provide means for locking the rotor shaft. Since it is frequently desired to manually rotate the shaft to control the voltage, it is necessary that the locking means on the shaft be releasable.

When the shaft is being manually controlled, however, there is a danger that excessive torque will be generated internally of the regulator and if means are not provided for preventing it, the torque may result in rapid rotation of the shaft and possible injury to the operator.

In the past it has been conventional to employ a simple crank-worm drive to control the rotor shaft of induction voltage regulators. While this type of drive does provide the locking and safety features that are desired, it does not permit the rapid adjustment of the rotor shaft that is frequently desired for small manually operated induction voltage regulators.

It is therefore an object of this invention to provide a shaft control means permitting the rapid manual adjustment of a shaft at the control means but preventing a rotation of the shaft by torque generated remotely from the control means.

It is also an object to provide a manually operated shaft control means permitting rapid adjustment of a shaft manually but locking the shaft against rotation effected by the generation of torque on the shaft remotely of the control, the control thereby preventing rotation of the shaft that may injure personnel operating the control.

Briefly stated, in accordance with one aspect of my invention, I provide a shaft control mechanism comprising a shaft, and a fixed annular friction member disposed coaxially with the shaft. The friction member is preferably disposed in a plane normal to the axis of the shaft. A pair of toggles are provided for movement in the plane of the friction member, and the toggles each have one end fixed to the shaft and their other ends resiliently held against the friction member. The end of the toggles bearing against the friction member are arranged to prevent rotation of the shaft in opposite directions. Means are provided for selectively disengaging the end of one of the toggles from the friction member to permit manual rotation of the shaft in one direction. The toggles may be arranged so that a member aflixed to the shaft comprises an arm common to both toggles.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention, it is believed that the invention will be better understood from the following description taken in connection with the accompanying drawing.

In the drawing:

Fig. 1 is a perspective partially cross-sectional view of a shaft control means according to my invention,

Fig. 2 is an enlarged top view of a portion of the QOII. tnol means of Fig. 1, and

Fig. 3 is an enlarged front view of the control means of Fig. 1 and illustrating the toggle and toggle release arrangement.

Referring now to the drawing, and more in particular to Fig. 1, therein is illustrated a shaft control mechanism for controlling rotation of a shaft 10. The shaft 10 extends through a plate 11, and the plate may be provided with corner studs 12 to facilitate mounting. For example, the shaft 10 may be the rotor shaft of an induction voltage regulator, and the corner studs 12 may serve to hold the plate 11 rigidly to the end of the frame of the regulator. An annular projection 13 is provided on one surface of the plate 11, the projection 13 having an annular internal surface 14 coaxial with the shaft 10 and disposed in a plane perpendicular to the axis of the shaft 10.

A hub 15 is rigidly aflixed to the shaft 10, as by a set screw 16, and a hub shaft 17 is provided rigidly afiixed to the hub 15 and extending parallel to the shaft 10. A pair of toggle arms 19 and 20 are pivoted on the hub shaft 17 and extend toward the annular friction surface 14. Thus, the arm 19 and the hub 15 form one toggle, and the arm 20 and the hub 15 form another toggle, the two toggles having the hub 15 as a common arm. The length of the toggle arms 19 and 20 from the center of the hub shaft 17 to their outwardly extending ends is greater than the shortest distance from the axis of the hub shaft 17 to the surface 14, and the toggle arms 19 and 20 extend toward the surface 14 on opposite sides of the radius of the annular surface 14 intersecting the axis of the hub shaft 17. Projections, such as studs 21 and 22 are provided extending parallel to the hub shaft from the toggle arms 19 and 20 respectively, and resilient means such as a helical spring 23 aflixed tothe studs 21 and 22 holds the ends of the toggle arms 19 and 20 against the friction surface 14, the force preferably being sufficient to prevent chattering When the mechanism is subject to oscillatory torque.

A knob 30 loosely mounted on the end of the shaft 10 (i.e., the diameter of the cavity of the knob is slightly larger than the diameter of the shaft) is pivoted on the hub shaft 17, and carries a projection 31 extending between the studs 21 and 22.

The screws 32 and 33 extending through studs 21 and 22 respectively engage the knob projection 31.

In the position of the control mechanism as illustrated in the drawing, clockwise torque applied directly to the rotor shaft 10 will result in a clockwise force on the hub shaft 17. Since the end of the toggle arm 20 is held against the surface 14 by action of the spring 23, the force of the hub shaft :17 tends to straighten the toggle comprised of toggle arm 20 and the common toggle arm (i.e., the hub 15). Movement of the hub shaft is restrained, however, since the length of the toggle arm is greater than the distance between the hub shaft Patented June 14, 1960 and surface 14, and increases in torque on the rotor shaft result only'in increases in pressure and frictional forces hetweenfthe toggle arm 20 and the surface 14, 'Lnerero'ra'ine locking 'action is produced-By the'driving' force on the rotonshaft; and the eorrect'iesfstance to sliding movementat the surface 14 is-gh'a'ranfed even if the torque ofthe nidtorshaft varies. I

- 'A'ny' movement of them" gle 'arr'n ze'win thefefdf' -be pivotal movement about the hub shaft 17. Fq1r--this reason it is-preferred thattheend of-jtlfe togglefarm engagingthe snrface 14 be curved, with the center of curvature being displaced 'frornthe hub "slf'a'ftfgene'rai-ly i'n -th'e direction that thehub shafttendstom ve so that any-'displace'nie'n't er the-hub shaft- 1 7 eausing he toggle arm to roll against the surraeen res ns in-"in" crease in the effective toggle arm length, thereby inaint'amm" g- (an e n' ebnsta'nt togglethe wg'giar'rem;abpieaen ger gde'adeenterp'os'i ti'oh; The curtatiiie-otthe tegglepemritseon- V ,siderable wear of the engaging stirfagewi thoutnppregiantm etin -the anneroraa naa sawaea the ea le surface. a i Movement of therotor shaft 10 resulting en mereloenwise torqueis similarly restrained byiheacnon of toggle Thejto'ggle 197mm 20 are in efi 'citual, owe er; preventing nhov'einent the-cloth; wa and e ohn'tercloekwise directions respectively; I

Since the 'k nob sfl is loosely inonnted on the end of V the 1Q; initialrnanual rotation of the-knobf results "o y in ixiviital inc ement-about the hub, shaft 17 until th '1='tw n thak b engages i ha i fo anrplmitis desired to turn the rotor shaft in a clock= i e d rec i itia r ha' f he no results onlyin 'anonyvisemqvpien at the knob about the hub 'shaft 17. The projection 31; affixed to the knob 3Q'a1so rotates in a tion, andforc'e s the'fs erew, 33: in the s ectthelifting of 'e toggle an; 20 a; shaft is m nm hF in 5 5 Mb I faab m 1 o; that theshafrt turns with ten hsitter s a t na Qi t ie r q b 30 is} aceornijlished as iniilariiiiannei', with ingrto, lift the toggle arrn '19 from it i i119 arpe s-su t? 7 3- th oto s l ine f qi lhe de o e; i m amt ie ii 9 I919;

is; being manually rotated clockwi jfi, and; a sudden .un er g arrn t 1 9,wj1l prevent:qrunteiiclockwise-rotation of the rotor shaft in response 'to the sudden torquei If, on the other kwise torque is applied to the, shaft, the't oggle the rotor shaft .is consequently leaked. against further clockwise rotation.

It willbe understood, of eonrse, that while the form of the invention herein shown and described constitutes the preferred embodiment of my invention, it is not intended herein to illustrate all of the possible equivalent forms or ramifications thereofi 'It will be understood that the words-employedare words of description rather gle and reventing than of limitation, and that various changes nay be made without-departing front the spirit-or sco er the invention herein disclosed, and his aimed in maap eaaeaclaims to cover allsuehchanges, as fall Within the true; spirit and scope of the invention a 7 V I U What I claim asset-v and desire-to secure by Letters Patent of the United States is:

1. A shaft control mechanism comprising a shaft, a fixed annular friction member coaxial with said shait, a

- said 'hand, theisndden torque'appliedto-the rotor shaft acts in thejsarne direction thatthehshaftis ibeingrn'anually rotated,

and thesudden movement isgfasierthan themovernent cansed-by;manual -'rotation movemen of the b aft 17 will result in the reengagiement ,ofthe, toggle arm ,with the surface "14 andQthe tconsequenttlockingt of the. rotor shaft. Thus; if the;rotor, shaft 10: is; beingmanually '7 rotated-fin a cloehwise direction, and aisnldden torque is aiiplied: on th'e motor shaft in the'sarne direction, if the antigen o'rqiie results in clockwise movernent of th'e pin 'flj-ifaster th'jaii tli'at provided by manual operation, a thouht if cl 'k wise detainee: or the knee "about the hub i :1 anmieiar countei'lclo'ckmse 'niovenient ha ft' 11 serves to o v lilif'; the ve a1 an er said toggles istheriaiaseris a ga v V inner surface er no on ineniber; said other links fijdt a non I, tiqns'with respeet'tothelen'g'th w ser i bf fi d'wmn i 'a-nr i on l i of saidotlrer links, and knob inean's disconnected from looseiy piyotedon said's'haftso that s'aid'iinob r'riefails are iiidebendently movable, said knob being, pivon the of said toggles, and said knee having tio'n rne'ans selectively e """ging Said ejctionsof thier 'linksto disengage o e, of the ends'fof said other 7 from said friction menibe'r.

in s .r ha lis P Q PB a a iee ii ew h ft, a xten n n o 'em agementwith the inner snrfaceofsaid friction,"

first shaftj, a pairrof toggle links pivoted o'n shaft an x't ridinfg'fint'o resilient en gemen with/the ac e of said friction n embe'r, said 7 links teend surf ac' on opposite sides of the nlane, of the said first and second shafts, a projection Ion Te Le "saidlinks eiiftendingjarallelto fs'aid first fshatt,

lmob means c'oaiiial with 'sa'id first than an av' nga g ta a r ra l s l ,sut va na a firs sha t being, disconnected therefrom so thataid knob -means andfir st sh aft are iridenendently niovable- 'saidknob {jeans ;p iyoted on said second, shaft,

d release 13 qt fi 9%? hi sa i n b, el' fi iti t l i i th pr tions of said links, gsaid release projectionhi'eans B' in arranged to; selectively: engage .lthelpr ojections ,of

ment in means for preventing injury of personnel oper ating a control knob comprising a fixed annular friction member coaxial with said shaft, a second shaft extending between the first mentioned shaft and said friction member, said second shaft being parallel to the first mentioned shaft, and mounted for rotation therewith, a pair of oppositely extending toggle links pivoted on said second shaft and extending into resilient engagement with the inner surface of said friction member, the extended lengths of said links being greater than the distance between said shaft and friction member, a projection on each of said links extending parallel to said first mentioned shaft, said control knob being pivotally mounted on said second shaft and having a central aperture therein coaxially receiving said first mentioned shaft, the diameter of said central aperture being slightly greater than the diameter of said first mentioned shaft so that said control knob and first mentioned shaft are separately movable independent of each other, a release projection afiixed to said knob and extending between the projections on said links, and said release projection being pivoted about said second shaft with said knob to selectively engage the projections on said links for disengaging the ends of said links from said friction member.

References Cited in the file of this patent UNITED STATES PATENTS 363,472 Lake May 24, 1887 692,869: Lemp Feb. 11, 1902 945,909 Chapman Jan. 11, 1910 980,003 Romines Dec. 27, 1910 2,440,630 Blocher Apr. 27, 1948 2,475,159 Spraragen July 5, 1949 2,703,499 Reid Mar. 8, 1955 FOREIGN PATENTS 384,026 France Jan. 23, 1908 481,511 Canada Mar. 4, 1952 

